The direct and indirect climatic effects of trace gas emission by oceanic biota are considered; it is shown that the highest potential sensitivities derive from the change in remote marine stratus cloud albedo due to dimethyl sulfide (DMS) emissions. As a paradigm for modeling trace biogas emissions, a hierarchy of box models is employed to explore the controlling variables on the biogenic production of this gas in the global ocean. This remote marine scenario is contrasted with the climatic and environmental impacts of coastal regions, and the coupling of the sulfur cycle with those of other trace gases is considered. The need to understand controlling variables and processes is stressed as a means to understand the stability of the system.